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The Last Word

Nodes of success

Q: Every time the Cook Islands government runs into a financial problem it
tells its citizens not to worry: tomorrow you are all going to be millionaires
because we have manganese nodules on our seafloor; lots of them. Photographs
show them quite densely packed but, unfortunately, they are 8 kilometres
down.

The government glosses over the problem of mining them and has given us the
impression that this is already being done elsewhere in the world but has never
given any details of where.

Can somebody tell me whether deep-sea nodules are being mined elsewhere and,
if not, just what problems mining them causes.

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A: The scepticism in the letter from Phil Evans of the Cook Islands is well
founded.

A group of entrepreneurs tried to get the necessary technology off the ground
(or, if you prefer, up to the ground) back in the 1970s. The group tried to
persuade the steel industry, which uses manganese in all steel, that terrestrial
manganese was in short supply. This is not the case, because there are more than
ample supplies in South Africa, Australia, Brazil and Russia. The problems of
mining seafloor manganese nodules include the cost of extraction, which is much
greater than land-based mining, and the question of ownership. The latter factor
is contentious as the recurring problem of who owns the world’s numerous
seafloor oil deposits has shown.

Another fly in the ointment is that the consumption of manganese in steel has
dropped quite markedly over the past three decades because of better controls in
steel processing. Therefore, the already extensive reserve life of existing
deposits has increased considerably.

There is no commercial extraction of manganese nodules anywhere in the
world, although there may be an odd pilot scheme somewhere, because even bad
ideas take a long time to die. It all comes down to economics, and extracting
manganese nodules from the ocean bed is probably just a little better than
mining on the moon—technically feasible but an economic joke. Then again,
it could happen—we have the Channel Tunnel and Concorde, for example …

The Cook Islands government would do much better to concentrate on tourism,
surely much more lucrative than manganese nodules. However, if they need a
consultant on deep-sea nodules, I would be happy to assist them. I would even
bring my own snorkel.

Anthony Sweeney

Darien, Connecticut, US

A: In the 1970s, the Hughes Corporation vessel Glomar Challenger embarked on
a high-profile project to investigate the commercial viability of harvesting the
manganese nodules scattered around the ocean floors of the world. Sometime
later, it transpired that this expedition was merely the cover for a clandestine
operation by the US government to find and raise a Soviet nuclear submarine that
had been sunk in the middle of the Atlantic.

There is an ample supply of manganese from land-based sources so, sadly for
your correspondent, the prospects for the profitable exploitation of the Cook
Islands resource seem small.

Stan Thomas

Wrexham, Clwyd

Pain gain

Q: As a back pain sufferer I have noticed two strange things. If I have a new
temporary pain such as a toothache, the back pain disappears for the duration.
Second, the back pain appears to get better or worse over an average period of
five days. Are these changes caused by endorphins, and if so how?

A: The toothache phenomenon can be explained by gate control theory. This
proposes a hypothetical gate which can open to allow pain messages through to
the brain, or shut to stop the messages. The gate is opened by factors such as
attention to pain or distress, and closed by factors such as
counterstimulation— for example the TENS (transcutaneous electrical nerve
stimulation) machine used to aid pain control in childbirth provides
counterstimulation. The more anxiety-provoking toothache pain, therefore,
competes with the back pain, so that only the former is registered.

However, it is important to remember that many chronic pain sufferers often
also report the opposite experience to your correspondent—any additional
illness or discomfort causes flare-ups in their constant pain, caused in part by
the extra strain and distress brought about by having to cope with another
stressor.

Chronic pain conditions such as back pain often follow a cycle of increased
pain followed by a period of reduced discomfort. This can occur within one
day—with pain often easier in the mornings but worse as the day
continues—or even longer periods as your correspondent describes. Such
fluctuations are often linked to activity level. When the sufferer is
experiencing a “good period” they will often attempt to do more, only to find
their pain intensity builds up and they eventually need to ease off and rest.
Their pain then diminishes over time until they are then experiencing another
good period. This cycle is often referred to as “overactivity: underactivity”
or, in the US, “burn and crash”, and can be broken by using the technique of
pacing taught on most pain management courses.

Endorphins do affect the experience of pain but are part of the sophisticated
interaction between many factors. To understand truly this complex area, a
biopsychosocial model often offers superior explanations to the more linear
models.

Katharine Treves

INPUT Pain Management Unit

St Thomas’ Hospital, London

This week’s questions

Up in smoke: I recently bought an ionisation smoke alarm and was surprised to
discover a small canister containing americium 241. There are no clues in the
instructions as to how the isotope detects smoke, apart form noting that steam
or condensation can also accidentally trigger the alarm. How does it work?

Jonathan Reis

Knutsford, Cheshire

Ice history: What happened to Erasto Mpemda, the Tanzanian student who in
1969 discovered that hot icecream mixture froze faster than cold mixture and
provoked a debate that is still going on in the pages of New Scientist
?

A. Kortlandt

Oxford

Garden gremlins: Would it be possible to breed a “super earthworm”? Or have
earthworms already attained the maximum size possible within the physical
limits imposed by a hydraulic skeleton?

Andrew Milligan

Colchester, Essex

Hot feet: I have an open fire. One day, pushing a log on the fire with my big
toe when wearing socks (admittedly, not advisable), a bluish-yellow flame
ignited and danced around my whole foot. The flame went out almost immediately,
but I felt the heat and there was a very faint smell of burning on the sock. The
socks were 60 per cent nylon, 40 per cent cotton and of summer weight—very
thin. The foot was relatively unwashed, warm and had just come out of a trainer.
Was the flame caused by the sock? Or do everybody’s feet give off methane, not
just mine?